io6 DIATOMS 



and post-tertiary strata. The Bergmehl of 

 Norway is composed of fresh-water species. 

 Small deposits have been found underlying 

 beds of peat in Great Britain and Ireland. A 

 bed 25 feet in thickness, composed entirely of 

 marine species, and extending over a large area, 

 occurs at Eichmond, in Virginia. Similar beds 

 exist in other countries. 



No mind, however mathematical, can have 

 any conception of the numerical strength of 

 these lowly yet magnificent organisms. For 

 example, in the Botanical Department of the 

 Natural History Museum, Cromwell Koad, a 

 glass case contains a block not more than 

 two cubic feet in measurement. It contains 

 not fewer than 12 billion (12,000,000,000,000) 

 individual plants ! This block representing so 

 much life could be carried under the arm 

 with ease. Figures must fail to help us when 

 trying to form an idea of the life repre- 

 sented in the deposit in the Antarctic Ocean, 

 48,000 miles in area, or in the fossil deposit 

 of Virginia. 



With regard to this almost cubical block, 



